use strict;
use warnings;
use Data::Dumper;

my $line = <>; chomp $line;
unless (length $line) {
  print 0;
  exit;
}

my @arr = split //,$line;
my $max = 1;
for (my $cent = 0; $cent < scalar @arr; $cent++) {
  for (my $plus = 0; $plus < 2; $plus++) {
    my $count = 1 - $plus;
    for (my $i = 1; ; $i++) {
      my $left = $cent - $i + $plus;
      my $right = $cent + $i;
      last if $left < 0;
      last if $right >= scalar @arr;
      $count += 2 if $arr[$left] eq $arr[$right];
    }
    $max = $count if $max < $count;
  }
}

print $max;